Systematic literature review of patient-reported outcome measures used in assessment and measurement of sleep disorders in chronic obstructive pulmonary disease

BACKGROUND Sleep problems are common in patients with chronic obstructive pulmonary disease (COPD), but the validity of patient-reported outcome measures (PROMs) that measure sleep dysfunction has not been evaluated. We have reviewed the literature to identify disease-specific and non-disease-specific sleep PROMs that have been validated for use in COPD patients. The review also examined the psychometric properties of identified sleep outcome measures and extracted point and variability estimates of sleep instruments used in COPD studies. METHODS The online EMBASE, MEDLINE, PsycINFO, and SCOPUS databases for all years to May 2014 were used to source articles for the review. The review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Criteria from the Medical Outcomes Trust Scientific Advisory Committee guidelines were used to evaluate the psychometric properties of all sleep PROMs identified. RESULTS One COPD-specific and six non-COPD-specific sleep outcome measures were identified and 44 papers met the review selection criteria. We only identified one instrument, the COPD and Asthma Sleep Impact Scale, which was developed specifically for use in COPD populations. Ninety percent of the identified studies used one of two non-disease-specific sleep scales, ie, the Pittsburgh Sleep Quality Index and/or the Epworth Sleep Scale, although neither has been tested for reliability or validity in people with COPD. CONCLUSION The results highlight a need for existing non-disease-specific instruments to be validated in COPD populations and also a need for new disease-specific measures to assess the impact of sleep problems in COPD.